Turf-like product and method of making it

ABSTRACT

A product having a turf-like appearance and useful as a playing field surface for football, baseball, or other games can be made in a wide variety of blade patterns and textures by (a) providing a liquid layer of polymeric matrix material (e.g., a foamable polyurethane composition) which can be solidified in situ to a desired degree of resilience and toughness; (b) providing a number of flexible polymeric ribbons; (c) making numerous widthwise cuts in one edge of each ribbon so as to form numerous blades (grass-blade-like elements) which are fastened together at their base; (d) forming a composite structure in which the ribbons are closely-spaced and in embedded relation with the liquid matrix layer whereby each ribbon has its length parallel with the matrix layer, its width perpendicular thereto, its blades upstanding therefrom, and a lower portion embedded therein; and (e) causing the matrix layer to solidify in situ.

United States Patent Nadler 1 June 27, 1972 [54) TURF-LIKE PRODUCT ANDMETHOD OF MAKING IT [72] Inventor: Martin L. Nedler, Wilmington, Del.

[73] Assignee: E. I. du Pont de Nemeurs and Company,

Wilmington, Del.

[22] Filed: Nov. 1', I970 [21] Appl. No.: 90,612

[52] US. Cl ..l6l/62, 156/72, 161/63, 16l/64, 161/67 [5 1] Int. Cl...D04h 11/00, A46d H00 [58] Field of Search ..l6l/62, 63, 64, 67; 156/72[56] Relerences Cited UNITED STATES PATENTS 2,001,970 5/1935 Mazer..l6l/64 3,513,061 5/1970 Vinicki... ..l6l/63 3,578,542 5/1971 Migitz..156/72 Primary Examiner-William J. Van Balen Attorney-Melville .l.Hayes [57] ABSTRACT A product having a turf-like appearance and usefulas a playing field surface for football, baseball, or other games can bemade in a wide variety of blade patterns and textures by (a) providing aliquid layer of polymeric matrix material (e.g., a foarnablepolyurethane composition) which can be solidified in situ to a desireddegree of resilience and toughness; (b) providing a number of flexiblepolymeric ribbons; (c) making numerous width-wise cuts in one edge ofeach ribbon so as to form numerous blades (grass-blade-like elements)which are fastened together at their base; (d) fanning a composite structure in which the ribbons are closely-spaced and in embedded relationwith the liquid matrix layer whereby each ribbon has its length parallelwith the matrix layer, its width perpendicular thereto, its bladesupstanding therefrom, and a lower portion embedded therein; and (e)causing the matrix layer to solidify in situ.

I 1 Claims, 4 Drawing Figures PATENTEDJUHZT I972 3.673 .056

FIG.3 FIG. 4 A l2 I l r 1 x r I mm NEE??? Wfi-W AGENT BACKGROUND OF THEINVENTION This invention relates to a product having a turf-likeappearance; it also concerns a process for manufacturing such a product.

There is a growing demand for man-made products having a turf-likeappearance and useful as a playing field surface. A natural turf playingfield for football, baseball, or other games is difiicult and costly tokeep in useful and attractive condition, especially when subjected tobad weather conditions, or insect attacks, or when the field gets veryfrequent or severe use. The many drawbacks of using a turf that is inpoor condition are well known in the art. It is also known that a fieldcan have a quality of natural turf that is not unduly objectionable fromthe standpoint of the players, but the overall appearance of the turf asviewed by the audience leaves much to be desired. When a game is to bewatched by a large television audience or by a large crowd in thestands, it is obviously desirable to have a playing field that is notonly useful for the players but also attractive to the audience.

SUMMARY OF THE INVENTION Expressed broadly, the present inventionprovides a process for preparing a product having a turf-like appearancewhich comprises a. providing a liquid layer of polymeric matrix materialwhich is capable of being solidified in situ,

b. providing a number of flexible polymeric ribbons,

c. forming one edge of each of said ribbons into numerous closely-spacedgrass-blade-like elements which are fastened together at their base byproviding numerous width-wise cuts of predetermined length along saidedge and leaving a portion of the ribbon uncut at the base of saidelements,

d. placing said ribbons in closely-spaced relation with each other andin embedded relation with said liquid matrix layer so that each of saidribbons has its length substantially parallel with the matrix layer, itswidth substantially perpendicular to the matrix layer, itsgrass-blade-like elements upstanding from the matrix layer, and a lowerportion embedded in the matrix layer, and

e. causing the matrix layer to solidify in situ.

The invention also provides a product having a turf-like ap pearance andcomprised of A. an in situ solidified matrix layer of polymeric materialand B. numerous closely-spaced flexible polymeric blade-containingribbons in embedded attachment with (A) and providing the upper surfaceof the product with a lawnlike appearance, each of said ribbons I.having its length substantially parallel with (A) and its widthsubstantially perpendicular to (A),

2. having as an uppermost portion numerous closelyspacedgrass-blade-like elements upstanding from (A) and fastened together attheir base, and

3. having a lower portion in embedded attachment with BRIEF DESCRIPTIONOF THE DRAWINGS The invention is illustrated in the attached drawingswherein:

FIG. 1 shows a perspective view of a sample of the turf-like productmade by embedding the lower uncut portion of ribbons of the type shownin FIG. 3 in a layer of polymeric matrix material.

FIG. 2 shows an enlarged fragmentary perspective view of a sample of theproduct whose structure is similar to that shown in FIG. 1.

FIG. 3 shows a side view of a polymeric ribbon resting on its lower edgeand having an upper portion which has been formed into numerousgrass-blade-like elements.

FIG. 4 shows a similar view of a ribbon having blades of various sizeand shape.

DESCRIPTION OF PREFERRED EMBODIMENTS In Step (a) of the novel process asdescribed above, there is provided a liquid layer of polymeric matrixmaterial which is capable of being solidified in situ. This liquidmatrix layer can be fon'ned first as a separate component followed byinsertion therein of the properly positioned ribbon components; or anassembly of the properly positioned ribbons (as required in Step d) andcan be fastened in place above a suitable casting surface or moldfollowed by allowing the liquid matrix material to flow onto the castingsurface and between the lower portions of the ribbons to be embeddedtherein. Either method can be carried out as a continuous process or asa batch process.

The matrix material used in Step (a) can be any known liquid polymericcomposition which is capable of being solidified in situ to form asolidified matrix layer having the properties needed according toparticular use intended for the product. A matrix material is used whichdoes not undergo any hamiful reaction with the ribbon components duringSteps (d) and (e), and which is low enough in viscosity to undergo asuitable rate of flow into the spaces between the ribbons.

A liquid matrix composition can be converted in Step (e) of the processto a solidified matrix layer by any one of such known methods asevaporating the organic solvent of a polymer solution, drying a polymerlatex, heating a plastisol or organosol, allowing a composition to cureor cross-link, for example with the aid of heat or an acceleratorcompound, or by combining two or more methods known to be useful forsolidifying a layer of liquid polymeric composition. When a cellularmatrix layer is desired, one can employ known foaming agents or othermeans known to be useful for preparing cellular sheets from liquidpolymeric compositions.

In some of the most useful embodiments of the invention, the solidifiedmatrix layer of the product (component A) is a flexible and resilientsheet of nonfibrous" polymeric material; this means that the polymericmaterial does not have a predominantly fibrous structure as in the caseof a fabric or paper, although it can contain a fibrous filler orreinforcement, and it can have a reinforcing fabric or any other usefulmaterial in attached or embedded relation with it.

Component (A) preferably has a thickness of about 0.2-1.5 inches in manyapplications of the product. It is also often preferred that thepolymeric material of component (A) be an elastomer. The polymericmaterial can be noncellular or cellular, the cells being either open orclosed. A closed-cell elastomer foam is preferred in some applications.

Component (A) can be a composite matrix made up of a plurality ofpolymeric layers of the same composition or dif ferent compositions. Insome cases it is beneficial to have an upper portion of the matrix whichdiffers from the lower portion in certain properties, for example inresilience, toughness, porosity, or resistance to degradation bysunlight.

One skilled in the art, in view of the present disclosure, will be ableto select suitable polymeric materials for the preparation of matrixcomponent (A) and ribbon component (B) according to the propertiesneeded and the conditions under which the product is to be used. Amongthe most useful polymers for both components are polyurethaneelastomers, neoprene, ethylene/propylene/diene elastomers,chlorosulfonated polyethylene, butadiene/styrene elastomers, naturalrubber, polyamides, polypropylene, and plasticized polyvinylchloride andthe like. The polymeric material used to form either component cancontain one or more of such known additives as pore-forming agents,coloring agents, curing agents, fillers, fireproofing agents,inhibitors, fungicides, and plasticizers.

The invention makes it easy to construct synthetic turfs fromelastomeric materials which provide good resistance of the blades andmatrix to undue stiffness or brittleness at low temperatures plus goodweather resistance, fire resistance, skid resistance, impact resistance,ball-bounce properties, and ability to retain a turf-like structureafter prolonged and repeated use. The resilient and skid resistantembodiments of the product tend to reduce the frequency of playerinjuries.

In Step (b), flexible polymeric ribbons are provided which have thedesired dimensions, toughness, weather resistance and other propertiesaccording to the intended use of the turflike product. Also, of course,the ribbons (component B of the product) are made of a material whichwill not undergo any harmful reaction with the matrix material eitherduring or alter Steps (d) and (e). The use of a single ribbon ascomponent (B) is also within the spirit of the invention since there isstill obtained a product having numerous closely-spaced ribboncomponents along its surface when a single ribbon is used in Step (d) bysuch procedures as by wrapping the ribbon back and forth over a seriesof holding pins fastened outside the matrix area or by mounting theribbon spirally in a suitable holding means fastened above the area tobe filled with the matrix.

A ribbon thickness of about 0.005-0.l inch is preferred in manyapplications of the product, with special preference for a thickness ofabout 0.0t-0.05 inch. A ribbon width of about 0.3-2.0 inches is alsousually preferred. In some embodiments, the ribbon thickness, width,stiffness, color, or other charac teristics vary from one ribbon memberto another, or from one portion to another portion of the same ribbon.For example, a ribbon can be used whose thickness gradually decreasesfrom the lower edge to the top; or a bead or groove can be provided nearthe lower edge to enhance the strength with which the ribbon is attachedto the solidified matrix. Also useful are ribbons made up of two or morelayers of similar or different materials; for example, the layers canhave different shrinkage properties, causing the blades of the productto curl; or the ribbon can be composed of a polymer-coated fabric.

In Step (c) of the process (see FIG. 3 of the drawings), numerouswidth-wise cuts of predetermined length are made in the ribbon along itsupper edge so that numerous grassblade-like elements (blades 12) areformed which are fastened together at their base, the cuts terminatingin an uncut portion ll of the ribbon. A blade length of about 0.2l.5inches is usually preferred. The blades can be uniform or nonuniform inheight, width, thickness, shape, color, or other characteristics. In themodification of FIG. 3 shown in FIG. 4 of the drawings there is anillustration of blades 12 of various size and shape formed by cuts 10which terminate at base portion ll; all or part of the blades in all orpart of the ribbons in a given product can have any one of these designsor any other design considered suitable.

By having the blades vary in any particular appearance characteristicalong the length or width of the product, it is possible to enhance theattractiveness or the random appearance of the product. Theblade-forming cuts can be made rapidly and economically by using cuttingmachines and techniques well known in the art of cutting predeterminedshapes in various kinds of ribbons, tapes, and the like. In one machine,an oscillating cutting blade strikes the ribbon as it rests on an anvilwhile the ribbon is moved along like in a sewing machine. The Step (c)cutting operation can be completed prior to Step (d); or incomplete cutscan be made prior to Step (d) which are easily broken open after Step(e), for example, by means of wire buffing wheels. Also, Step (c) can becarried out after Step (e) by subjecting the surface of the compositestructure to suitable cutting means such as cutting wheels or sharpknives.

Step (d) brings about the formation of a composite structure wherein theribbons are in closely-spaced relation with each other and in embeddedrelation with the matrix layer; each ribbon member has its length (e.g.,its bottom edge) completely or almost completely parallel with thematrix layer, its width completely or approximately perpendicular to thematrix layer, its blades (if out already) upstanding from the matrixlayer, and a lower portion embedded in the matrix layer. As is true withnatural turf, all or part of the blades in some embodiments of theproduct are not straight or perpendicular to the matrix. And in someembodiments only the lower portion of the blades extend upward from thematrix. A narrow space separates adjacent ribbon components; this spacecan be extremenly narrow when the liquid matrix material has arelatively low viscosity under the conditions used in Step (d). Heat,vibrating means, or pressure changes can be employed to enhance the flowof matrix material.

It is a preferred embodiment of the invention to fonn the compositestructure so that the ribbons are completely or almost completelyparallel with each other. It is also preferred that the space betweenadjacent ribbons be about 0.050.5 inch; the space can be uniform or itcan vary enough to enhance the random appearance of the product.

Before the properly oriented ribbons and liquid matrix material areallowed to come in contact with each other, the ribbons can be clampedtogether in a suitable clamping device with a removable spacer strip,for example a tape of polytetrafluoroethylene or polypropylene,interposed between the upper portion of adjacent ribbons. The abovementioned variation in space between adjacent ribbons will result byusing a predetermined variation in the thickness of spacer strips.

Synthetic turf products are obtainable according to the presentinvention having an attractive and durable lawn-like appearance andhaving beneficial utility as a surface material for areas on whichsports events such as ball games or other activities are performed. Theproduct can be made in any one of numerous predetermined patterns andtextures, and degrees of resilience or toughness or othercharacteristics. The present process is also useful for the manufactureof such products as buffing wheels, carpets for use outside or inside,and surfaces for golf-practicing areas in which different areas havedifferent predetermined ball-slowing characteristics.

The example which follows is given for the purpose of illustrating theinvention. All quantities shown are on a weight basis unless otherwiseindicated.

An attractive and durable product having a turf-like ap pearance anduseful in many applications where natural turf is used is prepared asfollows:

Two different batches of ribbons are prepared. First, a number offlexible polymeric ribbons are prepared having the appearance shown inFIG. 3 of the drawings. The ribbons are made of a toughweather-resistant elastomer material (described below) having agrass-like green color; they have a thickness of 15 mils (0.015 inch), awidth of IV4 inch, and a length of 12 inches.

Using a cutting apparatus equipped with a series of knife like cuttingdies, numerous width-wise cuts 10 are made in each ribbon along itsupper edge so that numerous grassblade-like elements or blades 12 areformed which are fastened together at their base. The cuts terminate inthe uncut portion 11 of the ribbon. Each cut is three-fourths inch longand the cuts are one-eighth inch apart; so blades 12 have a length ofthree-fourths inch and a width of one-eighth inch, and base portion 11is one-half inch wide (distance from the lower end ofcuts 10 to thelower edge of the ribbon).

In preparing the ribbons, the elastomer material is made by mixing theingredients of Formula l.1 below. ingredients [-9 are added in the ordershown to a water-cooled Model No. OOC Banbury Mixer and mixed at a speedof rpm until the temperature in the mixer reaches l77 C. The resultingmixture is placed on a two-roll rubber mill, and ingredients l0l 3 areadded gradually in the order shown while operating the mill at a lowenough temperature so that the temperature of 6 Silica I240 7 Oil 37.2 8Polyethylene 248 9 Green pigment 37.2 10 Z-mercaptobenzothinzyldisulfide12.4 11 Tetrarnethylthiuram diaulftde 8.68 12 Zincdi-n-butyldithiocarbamate 24.8 13 Sulfur 24.8

The numbered ingredients of Formula M are further described as follows:No. l is an elastomer terpolymer of 64 percent ethylene, 32 percentpropylene, and 4 percent 1,4- hexadiene; Mooney viscosity (ML 1 +4ll2lC.) of 60. No. 2 is an elastomer terpolymer of 72 percent ethylene, 24.5percent propylene, and 3.5 percent 1,4-hexadiene; Mooney viscosity (ML 110/ l 21 C.) of 60. No. 3 has a chlorine content of 35 percent and asulfur content of 1 percent; made from high-density polyethylene. No. 6is Silene" D from Pittsburgh Plate Glass Co., understood to be a mediumreinforcing hydrated silica pigment. No. 7 is Sunpar 150 from Sun OilCo., understood to be a nonstaining paraffinic oil; Sayboldt UniversalViscosity of 508 at 38 C. and of 64.3 at 99' C. No. 8 is a high-pressuretype branched polyethylene; melt index of 22, density of 0.925. No. 9 isa pigment known as Cl 74,260, Pigment Green 7 (Color Index," secondedition, Vol. 3). No. 13 is sulfur grade I030 Tube from StaufferChemical Co.

After the composition is thoroughly mixed, the preparation of theribbons is completed by (1) removing the composition from the mill inthe form of a sheet material; (2) transferring the sheet material whilestill hot to a 3-roll calender whose rolls are initially at about 22' C.and calendering the hot elastomer material so that it is rapidly madeinto a mil thick film; (3)winding the film with a cotton duck interlayerto form a roll, the roll being a cylinder which, when placed so that itsaxis is vertical, has a flat spiral top and bottom and a vertical sidecon-taining the outer ends of wound material; (4) sealing the roll byapplying adhesive tape over said outer ends and using tape to fasten acanvas cover over said spiral top and bottom; (5) curing the roll ofelastomer film in steam at 150 C. and 60 psi for 2 hours; (6) coolingthe cured film to room temperature and cutting it into H4. inch wideribbons; and (7) cutting the ribbons as described above to provideribbons of suitable length containing blades 12.

The cured and cooled film obtained in step (6) has the followingproperties:

Hardness 60 Tensile strength at break, psi 970 Modulus at 100%elongation, psi SSO Elongation at break, ii 270 The harness (ShoreDurometer A) is tested by ASTM Method D-2240-68. The modulus, tensile,and elongation values are obtained at room temperature by ASTM MethodD-4l2-68.

The cured film is cut into 1% inch wide ribbons; then the ribbons arecut as described above to provide ribbons of suitable length containingblades 12.

Next, in preparing the second batch of ribbons, a number of narrowerribbons are prepared by repeating the procedure described above exceptthe cured film is cut into inch wide ribbons, and the ribbons are cut sothat the blades 12 are three-eighths inch long and the base portion 11is one-half inch wide.

Enough of the ribbons from the resulting two batches and 12 inch longspacer strips of polytetrafiuoroethylene tape having a A inch width anda 6 inch thickness are used to form a 12 inch square assembly in aclamping device wherein the sequence of layers clamped together is (l) aribbon from the first batch, (2) a spacer strip, (3) a ribbon from thesecond batch, and (4) a spacer strip. Any known type of clamp can beused which is capable of holding the layers together in the mannerdescribed. The spacer strips are interposed between the upper (blade)portion of the ribbons. The ribbon assembly is mounted in a mold intowhich the matrix layer will be cast.

The mold has the general shape of a box whose inside measures about 12inches square by three-fourths inch deep. The lower edge of each of theribbons is one-eighth: inch above the bottom of the mold. The generalappearance of the ribbon assembly can be visualized by turning H6. 1upside down and imagining that it is the uncut base of the ribbonsinstead of the blades which project downward.

A foamable liquid polyurethane matrix composition capable of beingsolidified in situ to a closed-cell cellular elastomer structure havinga dirty brown color similar to that of good top soil is prepared bymixing the ingredients of Formula 1.2 shown below. Ingredients l-S aremixed together first; then the resulting mixture is mixed withingredient 6 at 22 C.

The numbered ingredients of Formula 1.2 are further described asfollows: No. l is Product C.P. 4701 from Dow Chemical Co., understood tobe a long chain polyether triol. No. 2 is Dabco" from Air Products andChemical Corp., understood to be a 33 percent solution oftriethylenediamine in a nonvolatile diol solvent. No. 4 is a mixture of95 percent methylene-bis-o-chloraniline and 5 percent 3-chloro-4,4'diaminodiphenylmethane. No. 5 is a pigment shown in the color lndex" asCl 77499, Pigment Brown 7. No. 6 is an undistilled mixture of percent2,4-toluene diisocyanate and 20 percent 2,6toluene diisocyanate, thetotal isocyanate content being 43 percent.

The matrix composition is poured into the mold to a depth sufficient toprovide a inch thick matrix layer after it is foamed and solidified. Thematrix material flows quickly into the space beneath and between thelower portions of the ribbons. Then the liquid matrix layer is exposedto air at 23 C. until it has foamed and solidified. Finally, the mold,clamping device, and spacer strips are removed from the resultingsynthetic turf product. If desired, the matrix layer can be prepared soas to contain a filler or fabric made of any suitable organic orinorganic material.

There has thus been formed a product having a composite structure asshown in FIG. 1 wherein the ribbons are in closely-spaced relation witheach other (oneeighth inch between the rows of blades 12 as measured atthe top of the matrix layer) and in embedded strongly attached relationwith the flexible and resilient matrix layer 13; each ribbon has itslength (see the lower edge of base 11 in HQ 2) parallel with the matrixlayer, its width (see base 11 and blades 12 in FIG. 2) aboutperpendicular to the matrix layer, its blades 12 upstanding from thematrix layer, and its lower portion 11 embedded in the matrix layer.

The product is useful as a playing field surface for various kinds ofball games and the like. The product can be made in any length or widthby making obvious modifications in the process described above, forexample, with respect to the length of ribbons and spacer strips, thenumber of ribbons in the ribbon assembly, and the size of the mold andclamps. Also a plurality of pieces of the product can be fastenedtogether by any suitable known fastening means (e.g., by stitchingand/or by using an adhesive), for example when covering a football fieldor other large area.

lclaim:

l. A process for preparing a product having a turf-like appearance whichcomprises a. providing a liquid layer of polymeric matrix material andfastened together at their base as the result of which is capable ofbeing solidified in situ, providing numerous width-wise cuts ofpredetermined b. providing a number of flexible polymeric ribbons,length along one edge of the ribbons and leaving a porc. forming oneedge of each of said ribbons into numerous i f th ibb uncut at th baseof the elements,

closely-spaced grass-blade-like elements which are fastened together attheir base by providing numerous width-wise cuts of predetermined lengthalong said edge and 3. having the lower base portion in embeddedattachment with (A).

and leaving a portion of the ribbons uncut at the base of 3 A Productaccording to claim 2 wherein component A) Said F is a flexible andresilient sheet of nonfibrous polymeric materid. placing said ribbons inclosely-spaced relation with each 10 a],

and in embcdded P with said quid matrix 4. A product according to claim2 wherein component (A) layer so that each of said ribbons has itslength substanhas a thickness ofabom 0245 inch.

tially parallel with the matrix layer, its width substantially 5' Aproduct according to claim 3 wherein the polymeric perpendicular to thematrix layer, its grass-blade-like elematcrial of component A) is anclastomcn from mam, layer and a 6. A product according to claim 5wherein said elastomer tron embedded in the matrix layer, and has acellular New:

;' z gg the ig i in d d 7. A product according to claim 2 wherein saidribbons have a u e appearan a thickness of about 0.00541] inch.

l B. A product accordlng to claim 7 wherein said ribbons have A. an Insitu solidified matrix layer of polymeric material a thickness about 00m0050mm and 9. A product according to claim 2 wherein said rlbbons haveB. numerous closely-spaced flexible polymeric blade-cona width of about0. 34 inches.

mining ribbons in embedded attachment with (A) and 10 A productaccording to claim 9 wherein said grass f th od l wnproviding the uppersurface 0 6 pr um mm a a blade-like elements have a length of about0.2-1 .5 inches.

'k -bbo h e appearance each of sald n ll. A product according to claim 2wherein said ribbons are 1. h tsl th bst t'all allel with A and its 3:gd ggg z z igzi (A) substantially parallel with each other and thespace between 2. having as an uppermost portion numerous closelyadjacent"bbonsls abGut spaced grass-blade like elements upstanding from (A)

2. A product having a turf-like appearance and comprised of A. an insitu solidified matrix layer of polymeric material and B. numerousclosely-spaced flexible polymeric blade-containing ribbons in embeddedattachment with (A) and providing the upper surface of the product witha lawn-like appearance, each of said ribbons
 2. having as an uppermostportion numerous closely-spaced grass-blade like elements upstandingfrom (A) and fastened together at their base as the result of providingnumerous width-wise cuts of predetermined length along one edge of theribbons and leaving a portion of the ribbons uncut at the base of theelements, and
 3. having the lower base portion in embedded attachmentwith (A).
 3. A product accoRding to claim 2 wherein component (A) is aflexible and resilient sheet of nonfibrous polymeric material.
 4. Aproduct according to claim 2 wherein component (A) has a thickness ofabout 0.2-1.5 inches.
 5. A product according to claim 3 wherein thepolymeric material of component (A) is an elastomer.
 6. A productaccording to claim 5 wherein said elastomer has a cellular structure. 7.A product according to claim 2 wherein said ribbons have a thickness ofabout 0.005-0.1 inch.
 8. A product according to claim 7 wherein saidribbons have a thickness of about 0.010-0.050 inch.
 9. A productaccording to claim 2 wherein said ribbons have a width of about 0.3-2.0inches.
 10. A product according to claim 9 wherein said grass-blade-likeelements have a length of about 0.2-1.5 inches.
 11. A product accordingto claim 2 wherein said ribbons are substantially parallel with eachother and the space between adjacent ribbons is about 0.05-0.5 inch.